Power electronic and optoelectronic devices with interdigitated electrodes

Abstract

This invention relates to interdigitated electrodes for power electronic and optoelectronic devices where field and current distribution determine the device performance. Described are geometries based on rounded asymmetrical fingers and electrode bases of varying width. Simulations demonstrate benefits for reducing self-heating and thermal power loss, which reduces overall on-state resistance and increases reverse break down voltages.

The invention claimed is: 
     
       1. A semiconductor device, comprising:
 at least two electrodes, each of said at least two electrodes comprising an electrode base having a continuously tapered side; 
 a plurality of asymmetrical fingers extending from the continuously tapered side of each of said at least two electrodes; 
 wherein each asymmetrical finger is asymmetrical about its longitudinal axis; 
 wherein the asymmetrical fingers of the at least two electrodes are interdigitated; 
 a semiconductor channel between the interdigitated asymmetrical fingers of the at least two electrodes; 
 wherein each asymmetrical finger has a smooth shape without angular corners. 
 
     
     
       2. The semiconductor device of  claim 1 , wherein a finger tip of each asymmetrical finger has a circular shape. 
     
     
       3. The semiconductor device of  claim 1 , wherein a finger tip of each asymmetrical finger has an oval shape. 
     
     
       4. The semiconductor device of  claim 1 , wherein a finger tip of each asymmetrical finger has a shape defined by a power function, wherein the power is two or greater than two. 
     
     
       5. The semiconductor device of  claim 1 , wherein the continuously tapered side of each electrode base is tapered according to a selected angle;
 wherein a width of each electrode base varies linearly according to the selected angle. 
 
     
     
       6. The semiconductor device of  claim 5 , wherein a shape each electrode base is substantially a right-angle triangle. 
     
     
       7. The semiconductor device of  claim 6 , wherein each electrode base comprises a bounding box of right-angle triangle with bonding pads at two or three corners. 
     
     
       8. The semiconductor device of  claim 1 , wherein the continuously tapered side of each electrode base is tapered according to a mathematical function;
 wherein a width of each electrode base varies non-linearly according to the mathematical function. 
 
     
     
       9. The semiconductor device of  claim 1 , wherein the continuously tapered side of each electrode base is tapered according to ratio (GR) between remaining current flow and current flow to a next asymmetrical electrode finger. 
     
     
       10. The semiconductor device of  claim 1 , wherein the continuously tapered side of each electrode base provides current density uniformity across the plurality of asymmetrical fingers. 
     
     
       11. The semiconductor device of  claim 1 , further comprising a control electrode coupled to the semiconductor channel between the interdigitated asymmetrical fingers;
 wherein the control electrode is operable to interrupt or complete the semiconductor channel. 
 
     
     
       12. The semiconductor device of  claim 1 , wherein the continuously tapered side of a first electrode base is tapered at a different angle from the continuously tapered side of a second electrode base. 
     
     
       13. The semiconductor device of  claim 1 , wherein the continuously tapered side of a first electrode base is tapered at the same angle as the continuously tapered side of a second electrode base. 
     
     
       14. A method for implementing a semiconductor device comprising:
 providing each of at least two electrodes of the semiconductor device with an electrode base having a continuously tapered side; 
 providing a plurality of asymmetrical fingers extending from the continuously tapered side of each electrode base, wherein each asymmetrical finger is asymmetrical about its longitudinal axis; 
 wherein the asymmetrical fingers of the at least two electrodes are interdigitated; 
 providing a semiconductor channel between the interdigitated asymmetrical fingers of the at least two electrodes; 
 wherein each asymmetrical finger has a smooth shape without angular corners. 
 
     
     
       15. The method of  claim 14 , comprising implementing a finger tip of each asymmetrical finger with a circular shape. 
     
     
       16. The method of  claim 14 , comprising implementing a finger tip of each asymmetrical finger with an oval shape. 
     
     
       17. The method of  claim 14 , comprising implementing a finger tip of each asymmetrical finger with a shape defined by a power function, wherein the power is two or greater than two. 
     
     
       18. The method of  claim 14 , wherein the continuously tapered side of each electrode base is tapered according to a selected angle;
 wherein a width of each electrode base varies linearly according to the selected angle. 
 
     
     
       19. The method of  claim 14 , wherein the continuously tapered side of each electrode base is tapered according to a mathematical function;
 wherein a width of the electrode base varies non-linearly according to the mathematical function. 
 
     
     
       20. The method of  claim 14 , wherein the continuously tapered side of each electrode base is tapered according to a flow ratio (GR) between remaining current flow and current flow to a next asymmetrical finger. 
     
     
       21. The method of  claim 14 , wherein the continuously tapered side of each electrode base provides current density uniformity across the plurality of asymmetrical fingers. 
     
     
       22. The method of  claim 14 , further comprising coupling a control electrode to the semiconductor channel between the interdigitated asymmetrical fingers of the electrodes;
 wherein the control electrode is operable to interrupt or complete the semiconductor channel. 
 
     
     
       23. The method of  claim 14 , wherein the continuously tapered side of a first electrode base is tapered at a different angle from the continuously tapered side of a second electrode base. 
     
     
       24. The method of  claim 14 , wherein the continuously tapered side of a first electrode base is tapered at the same angle as the continuously tapered side of a second electrode base.